Cooling circuit for an internal combustion engine

ABSTRACT

In a cooling circuit for an internal combustion engine including a cylinder block with a cylinder head wherein the cooling circuit includes a coolant pump with a coolant duct extending from the pump to the engine for supplying coolant thereto, the coolant duct includes a valve arranged between the coolant pump and the engine for controlling the flow of coolant through the coolant duct to the engine.

BACKGROUND OF THE INVENTION

[0001] The invention relates to a cooling circuit for an internalcombustion engine of a vehicle including an engine block with at leastone cylinder head to which coolant is supplied from a coolant pump byway of a coolant pipe.

[0002] DE 197 41 861 A1 discloses a cooling circuit for an internalcombustion engine wherein the cooling water flow through the internalcombustion engine is controlled by a thermostatic valve which isarranged in the cooling circuit in flow direction after the internalcombustion engine.

[0003] A similar cooling circuit is shown in DE 195 06 935 C1.

[0004] Both of these cooling circuits however have the disadvantagethat, in spite of relatively involved switching arrangements and otherefforts, there is only insufficient waste heat available to a heater forheating the interior of the vehicle during the engine warm-up period.

[0005] It is therefore the object of the present invention to provide acooling circuit for an internal combustion engine with which theinternal combustion engine reaches operating temperatures more rapidlythat is the coolant flowing through the heater connected to the enginefor heating the vehicle interior is rapidly heated for heating thevehicle interior.

SUMMARY OF THE INVENTION

[0006] In a cooling circuit for an internal combustion engine includinga cylinder block with a cylinder head wherein the cooling circuitincludes a coolant pump with a coolant duct extending from the pump tothe engine for supplying coolant thereto, the coolant duct includes avalve arranged between the coolant pump and the engine for controllingthe flow of coolant through the coolant duct to the engine.

[0007] With the valve arranged between the coolant pump and the internalcombustion engine, it is easy to control the coolant volume flow throughthe internal combustion engine.

[0008] It is for example possible with the valve arrangement accordingto the invention to keep the coolant duct fully closed while theinternal combustion engine is cold so that no coolant is supplied to theinternal combustion engine and the coolant disposed in the engine israpidly heated. When the coolant is sufficiently heated the valve can beopened so that the coolant can circulate in the normal manner.

[0009] It is also possible to adjust the valve to provide a certaincoolant volume flow through the coolant duct to the engine.

[0010] The coolant flow through the engine can be accurately and finelycontrolled if, as in a preferred embodiment of the invention, the valveincludes a closure element for blocking the coolant flow and the closureelement is under full control of an operating mechanism with a controldevice.

[0011] Advantageous embodiment of the invention will become apparentfrom the following description on the basis of the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 shows schematically the engine cooling circuit according tothe invention,

[0013]FIG. 2 is a schematic representation showing the arrangement ofthe coolant pump on the engine, and

[0014]FIG. 3 shows an arrangement for operating a coolant flow controlvalve.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0015]FIG. 1 shows a cooling circuit 1 for an internal combustion engine2 comprising an engine block 3 on which a cylinder head 4 is disposed.The cooling circuit 1 includes the following: a duct 6 extends from acooler 5 to a coolant pump 7 from which a coolant duct 8 extends to theengine block 3. The coolant duct 8 includes a valve 9 whose functionwill be explained later. The coolant reaching the engine block 3 by wayof the coolant duct 8 (for example cooling water) can, as indicated bythe arrow 10, enter the cylinder head 4 as indicated by the arrow 10. Itleaves the cylinder head 4 through a coolant return line 11 towardthermostat 12 or through a line 13 to an exhaust gas re-circulationcooler 14. It would of course also be possible to supply the coolant tothe cylinder head 4 of the internal combustion engine 2 and to return itfrom the engine block 3. However, the arrangement as shown in FIG. 1 isconsidered to be the thermally better solution.

[0016] The thermostat 12 is in communication with the coolant pump 7 byanother line 15, and with the cooler by a line 16. Finally, a line 17,which extends through an engine oil heat exchanger 18 to the engineblock 3, branches off the coolant return line 11. The flow direction ofthe coolant through the lines 6, 8, 11, 13 15, 16 and 17 is clearlyindicated by the arrows in FIG. 1.

[0017] With the valve 9 as described, the coolant duct 8 which leads tothe internal combustion engine 2 can be closed or opened. Also,intermediate valve positions are possible for obtaining a certain volumeflow. When the coolant duct 8 is completely blocked no coolant can flowto the internal combustion engine 2 so that the coolant contained in thecylinder head 4 is much more rapidly heated than would be the case witha continuous coolant flow through the cylinder head. A blocking of thecoolant duct 8 by the valve 9 is therefore especially appropriate duringa cold start of the internal combustion engine 2 since, with the fasterheating of the coolant, a faster heating of an interior space of avehicle in which the internal combustion engine is disposed is achieved.

[0018] The temperature of the coolant is sensed by one or severaltemperature sensors 19, 20 or, respectively, 21 and passed on to acontrol unit 22 which is connected to the valve 9. When the coolant inthe internal combustion engine 2 or in the coolant duct 8 reaches, inthe area between the valve 9 and the internal combustion engine 2 or inthe coolant return line 11 between the internal combustion engine 2 andthe thermostat 12, a certain temperature, a signal is provided by thecontrol unit 22 for controlling the valve 9. The valve 9 can then be socontrolled that the volume flow of the coolant in the coolant pipe 8 isadjusted so that, depending on the requirements of the internalcombustion engine 2, an appropriate amount of coolant is permitted toflow to the engine block 3 and from there to the cylinder head 4.

[0019]FIG. 4 shows the engine block 3 of the internal combustion enginewith four combustion chambers 23. Of course, the block 3 may haveanother number of combustion chambers 23. At the front end, the engineblock 3 includes a chain casing 24 for containing a camshaft drive chainwhich, however, is not shown. At its outer side, the chain casing isprovided with a chain casing cover 25. Mounted on the chain casing cover25 is the coolant pump 7. The coolant duct 8 extending through thecamshaft drive cover 25 and the drive housing 24 to the engine block 3is also shown in FIG. 2. Also, the valve 9 is shown again schematicallyin the coolant duct 8 between the coolant pump 7 and the internalcombustion engine 2. In this case, the coolant duct 8 extends throughthe engine. In the arrangement as shown in FIG. 2, the valve 9 istherefore arranged within the internal combustion engine 2.

[0020] As shown in FIG. 3, the valve 9 includes a closure element 26 forblocking the coolant duct 8, which is controllable by an operatingmechanism 27 connected to the closure element 26. In the arrangement asshown, the closure element 26 is a gate valve, which is capable of fullyclosing, completely opening or partially opening the coolant duct 8.

[0021] The operating mechanism 27 may be for example an electric controlmotor, a vacuum operator or an electromagnet. As explained earlier theoperating mechanism is controlled by the control unit 22.

What is claimed is:
 1. A cooling circuit for an internal combustionengine including a cylinder block and a cylinder head mounted on saidcylinder block, said cooling circuit including a coolant pump, a coolantduct extending from said coolant pump to said engine for supplyingcoolant thereto, and a valve arranged in said coolant duct between saidcoolant pump and said engine for controlling the flow of coolant throughsaid coolant duct to said engine.
 2. A cooling circuit according toclaim 1, wherein said valve includes a closure element for fullyblocking said coolant duct and an operating mechanism for actuating saidclosure element.
 3. A cooling circuit according to claim 2, wherein saidclosure element is a gate valve slide.
 4. A cooling circuit according toclaim 1, wherein said coolant duct extends from said coolant pump tosaid engine block so that coolant is supplied by said pump to saidengine block when said valve is not close d and said coolant flows fromthe engine block to the cylinder head and wherein a coolant return lineis connected to said cylinder head.
 5. A cooling circuit according toclaim 2, wherein said operating mechanism is an electric control motor.6. A cooling circuit according to claim 2, wherein said operatingmechanism includes a vacuum operator.
 7. A cooling circuit according toclaim 2, wherein said operating mechanism includes an electromagnet. 8.A cooling circuit according to claim 1, wherein said coolant pump ismounted directly to said engine, said coolant duct extends from saidpump through said engine and said control valve is arranged within saidengine.